Isolation of mono-iodotyrosine from slightly iodinated pepsin has been repeated and the properties of the product compared with those of synthetic dl-3-iodotyrosine. Ultraviolet absorption spectra, pK values of the phenol group, solubility measurements, and partition coefficients were so nearly identical for the two materials that there is now no reason to doubt that the product from pepsin is 3-iodotyrosine.

This content is only available as a PDF.